Sight unseen: vision and perception in Leonardo's Madonnas: in the first of two articles on Leonardo da Vinci, Larry J. Feinberg explains how the artist's interest in the way the eyes work influenced his realistic depictions of the Christ Child as a baby learning to see

Apollo, July, 2004 by Larry J. Feinberg

(13) Kenneth Clark and Carlo Pedretti, The Drawings of Leonardo da Vinci in the Collection of Her Majesty the Queen at Windsor Castle. London and New York, 1969, vol. III, pp. 56-57, and see Martin Kemp, 'Leonardo and the Visual Pyramid', Journal of the Warburg and Courtauld Institutes, vol. XL, 1977, p. 129, and James S. Ackerman, 'Leonardo's Eye', Journal of the Warburg and Courtauld Institutes, vol. XLI, 1978, p. 127. Leonardo reiterated this opinion several years later on a page in the Codex Atlanticus (c. 1485-90; fol. 270 v.c.); see MacCurdy, op. cit., vol. I, p. 249, and Kemp, op. cit. in n. 1 above, p. 130.

(14) Leon Battista Alberti, On Painting and Sculpture, edited and translated by Cecil Grayson, London, 1972, p. 41.

(15) Elaheh Kheirandish, the Arabic Version of Euclid's Optics, New York, 1999, vol. I, pp. 2-4, vol. II, pp. 15-19; and Plato: Timaeus, Critias, Cleitophon. Menexenus, Epistles, translated by R.G. Bury, Cambridge, Mass., and London, 1999, line 45, pp. 101-102.

(16) Kemp, op. cit. in n. 1 above, p. 130 and fig. 17; idem, op. cit. in n. 12 above, pp. 46-47, fig. 77 and p, 50, fig. 85; end Leonardo da Vinci, II Codice Atlantico della Biblioteca Ambrosiana di Mileno, transcription by Augusto Marinoni, Florence, 2000, fol. 232, vol. I, p. 365. Also see Leonardo's notes on fol. 270 of the Codex Atlanticus in MacCurdy, op. cit., vol. I, p. 252: and Kemp, op. ctr. in 1 above, p.130, fig. 17. In reality, visual information is not transmitted to the area where the optic nerve attaches to the retina, which is called the 'blind spot,' but to the 'yellow spot' (fovea) located on the retina above the entrance to the optic nerve. For Leonardo's ideas and drawings (Windsor 12603, 12626, and 12627 [c. 1493-94], 12602 [c. 1504-08], 19052 [c. 1489], and 19070 [c. 1508], and Schlossmuseum, Weimar [c. 1506-1508]) concerning the transmission of visual information to the imprensiva, see Clark and Pedretti, op. cit., vol. I, pp. 122, 123, and 130, vol. III, pp. 22 and 29; Kenneth D. Keele and Cado pedretti, Leonardo da Vinci: Corpus of the Anatomical Studies in the Collection of Her Majesty the Queen at Windsor Castle, London and New York, 1979, vol. I, pp. 164-67; Kenneth D. Keele, Leonardo da Vinci's Elements of the Science of Man. New York and London, 1983, pp. 69-71 and 76, figs. 2.32, 2.33, and 2.40; and Kemp, op. cit. in n. 1 above, pp. 125-31. In Leonardo's imaginative, neo-Aristotellan, three-ventricled scheme of the brain, the imprensiva, supposedly the receptor of impressions, may have been his designation for the cingulate gyrus. Alberti, op. cit., p. 41, chose to avoid the issue of post-ocular transmission.

(17) British Museum, no. 1860-6-16-100. See Carmen Bambach et al., Leonardo da Vinci: Master Draftsman, exh. cat., Metropolitan Museum of Art, New York, 2003, no. 20, pp. 296-300. The studies are executed in matalpoint, pen and ink, and wash. The optical diagrams are executed in the same leadpoint as the underdrawings of the Virgin and Child studies on both recto and verso and so most likely preceded Leonardo's application of pen and ink. I am grateful to Dr. Bambach and Hugo Chapman for permitting me to examine the sheet closely after its deinstallation from the Leonardo exhibition at the Metropolitan Museum.